Technology to substantially reduce commercial ship fuel consumption by harnessing sea winds for simultaneous generation of electricity and thrust, has been developed by the company PROPit AB. The basic idea is to apply conventional wind turbine technology for the marine environment, where the turbine will also take the function of sails. Primary target market is tankers or bulk ships with a large and open deck space. Chalmers, in a study co-sponsored by the Swedish Energy Agency and Chalmers Energy Centre, 2011, confirmed fuel saving estimates around 15-30 % for optimal routes, but with higher uncertainties. The project objective was to examine and validate technology for the use of wind power on-board commercial ships. The specific topics were studied in eight discrete work packages: 1. Optimal design of a wind turbine for ships. 2. Suitable generator technology. 3. Principles for wind energy conversion. 4. Route optimization systems in the market, for integration with a wind turbine installation. 5. Wind conditions on a set of selected commercial sea routes. 6. Safety risks and conditions for class approval of ships with wind turbines. 7. Conditions for the fastening of a wind turbine and the effect on ship stability. 8. Design, construction and test of a prototype turbine